1. Field of the Invention
The present invention relates to a communication system making use of wireless LAN, and more particularly to a communication system by an access point (hereinafter, referred to as AP) in streaming communication.
2. Description of the Related Art
Heretofore, there is known streaming communication for carrying out audio communication and motion picture communication at a real time as a communication mode making use of a wireless LAN system. In general, in the streaming communication, communication can be carried out smoothly when the number of communications at an AP is relatively small. However, as the number of communications increases, since the communication band of the AP is oppressed, a packet is liable to be delayed or discarded. Thus, a disadvantage such as disconnection of communication and the like occurs on a terminal side, which makes it difficult to carry out communication comfortably.
To overcome the problem, conventional technologies propose to physically disperse a system load by installing a plurality of APs. As a kind of the technologies, there is a technology for prompting wireless connection to AP in a lower load state by that an AP in a higher load state forcibly disconnects the wireless connection of some terminal apparatuses. A technology relating to the above technology is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-124939 to be described below.
Further, there is also a technology for maintaining a load uniform in such a manner that a plurality of APs exchange load state information, and an AP having a high load reduces the strength of radio wave and an AP having a low load increases the strength of radio wave. A technology relating to the above technology is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2004-140614 and 2004-320274 described below.
Incidentally, to comfortably carry out streaming communication, the number of communications of APs must be taken into consideration. When, for example, IEEE802.11b is used as a standard of wireless LAN in a network to which VoIP (voice over Internet Protocol) is applied, the number of connections to one AP must be made to 10 or less to carry out audio communication comfortably.
Although the conventional method described above is effective to disperse the load of an AP, it pays no attention to keep the number of communications of the AP. Accordingly, even if the load is dispersed, there is a possibility that communication quality is deteriorated by that the number of communications of one set of an AP exceeds an upper limit.